Circuit breaker



July 4, 1933. A, c AGQ 1,916,418

CIRCUIT BREAKER Filed Aug. 29, 1927 3 Sheets-Sheet 2 Fig.

a Load Generator INVENTOR A1077 a'f'aggzai y Sam 1/8711 Q AdministrazozATTORNEY A. C. CRAGO CIRCUIT BREAKER July 4, 1933 Filed Aug. 29', 1927 3SheetswSheet 3 Fig. 6.

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AT'OEY Patented July 4, 1933 UNITED STATES PATENT OFFICE ALAN C. GBAGO,DECEASED, LATE OF PITTSBURGH, PENNSYLVANIA, BY SAMUEL ID.

CBAGO, ADMINISTRATOR, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOB TO WEST-INGHOUSE ELECTRIC & MANUFACTURING COHI PANY, A CORPORATION OF PENNSYL-VANIA CIRCUIT BREAKER Application filed August 29, 1927. Serial No.216,032.

The invention relates to circuit-interrupting devices and particularlyto are extinguishing means for use in connection there- I with.

The principal field for immediate application of the invention is inconnection with alternating current circuit breakers, and there will behereinafter described an embodiment of the invention as applied to suchcircuit breakers without in any way intending to restrict the scope ofthe invention, except as indicated in the appended claims.

One object. of the invention is to provide means for interrupting theflow of electricity through a gaseous medium.

Another object of the invention is to provide a circuit breaker with anarc-interrupting device capable of opening high voltage, large currentarcs in air or gas without recourse to oil or other are quenching media.In some of its aspects, however, the invention is applicable inconnection with low power circuit interrupting devices and to a varietyof other uses.

Another object of the invention is to provide a structure wherein an arcmay be operated in proximity to metallic deionizing means without beingsplit up into a plurality of short'sections operating from cathodes onthe metallic members. 1

A further object of the invention is to provide a deionizing chamber forcircuit interrupters comprising a plurality of metallic rods so arrangedthat an arc can be forced to operate in the interstices between themwithgut destruciive melting of the metallic memers.

Further objects of the invention will become apparent through readingthe following description taken in connection with the drawings whereinFigure 1 is a View in elevation, partly in section, of a circuitinterruptingdevice embodying the deionizing structure of the invention,I Fig. 2 is a sectional view taken on the lines from 11-11 of Fig. 1,

Fig. 3 is an enlarged plan view of the interrupting device shown in Fig.1,

Fig. 4 is adiagram illustrating certain circult connections employingthe invention,

Fig. 5 is a diagram used in explaining the v invention, 1

Fig. 6 is a similar explanatory diagram,

Fig. 7 is a detail of one form of an element of the deionizing structureembodying the invention, and

Fig. 8 is a detail of another form of an element embodied in thedeionizing structure of the invention.

Patent 1,819,207, issued Aug. 18, 1931, on an application of JosephSlepian, assigned to the Westinghouse Electric & Manufacturing Co.describes a circuit breaker provided with a deionizing structure whichextingui shes the arc incident to the opening of its main contact, thisdeionizing structure comprising a series of sheets of metallic gauzethrough the openings of which the arc is compelled to run, and by whichthe arc path is rapidly deionized at the instant when the main currentfalls to -zero in its alternating current cycle.

While deionizing structures of this type have been, in general, found tobe eminently satisfactory, certain conditions of line voltage, frequencyand current may exist in which the arc has been found to cease tooperate in the interstices of the gauze and to split up into a series ofshort arcs between successive gauze sheets.

Figure 5 diagrammatically illustrates such a breaking up of the are intoa series of short sections. Each of these short arcs has a cathode andan anode on the wire gauze and these may cause a melting of the metal,and a destruction of the sheet thereby. the arc plays between arctermlnal members 35 and 36 between which are placed wire gauze sheets37, as disclosed in the patent referred to above. In such a structure,under some conditions, the'arc may be split up into short sections suchas shown at 38a, 38b, and 380, etc. The path of the current would thenbe, for example, from terminal 35, through arc section 38a to gauzesheet 37a and then in the sheet 37a to the terminal of arc section 38?)which conducts the current to sheet 376. The current then flows in sheet100 In Fig. 5'

37% to the tcrminui of arc section 38c'u-nd so on through the remainingare sections and sheets to the arc terrninei member 36, This means thatthe totui are current wiii he flowing' vertically in the sheets and musttronsfor from each sheet to the arc sections ploy ing thereon, Thistransfer of the current- .irorn the sheets to the arc sections makes itpossihie for s hot cathode to term st one terminci oi each arc sectionend on anode ct the other terminci with s resuiting burning of the genessheets, uniess the are moved quite In accordance with the invention,hreohing up cit-the are into short sections with the consequentdestruction of the deionizing sheets verticci cross conductors as whenwire) gauge is used, so that the current could oniy flow through theseries of short orcs by pussing from s rod in one horizontui row to arod in another horisontoi row through the end connections 26. Sincethese int-liter ore" of high resistance there must he s considerehievoltage drop through this resistance and it is consequently morediiiicuit for theerc to opcrate in or series of short srcsinterconnected by this high resistance than it is for it to operute us asingle tong are 39, such as that illustrated in Fig. 7 t, in n pathconfined to sir spaces between the rods. The conducting hers 25 thusprovide conducting puths ecross the ore extinguishing chsmher 021317 inc direction which is hoth trensverse to the iength of the ore end transverse to the direction of movement of the arc. This meshes more dificuitfor the ore to he split up into short us it is moved into the conductineierneuts and uroids the formstion of t ermionic cathodes which wouldcause turning off the conducting elements st the hose or eech short one.

Referring to the drawings, the circuit hrecher in which the invention ishere emhodied comprises s, pair of main contact menuhers 1 end 2arranged to he bridged by a contact brush 3 heid upon as rosincontecturm 4. The srni is pivoted to swing the hrush hetween theposition in which it hridges the mein contract members and the positionaway from said contact members in which the circuit oreuher is-opened. I

7 The arm i is moved hetween its closed and 7 open position by rneensofu iinh 5 end toggle mechanism or at design too weii imown in the ert torequire extended description here}.

moronic The circuit hreoher is further provided with an arc interruptingstructure 6 com prising on arcing contact arm. 7 having at its upper endso arcing contact shoe 8 to engage u stationery arcing contact member-9for finally interrupting the circuit. The arcing shoe 8 end thestationery arcing Contact incinher 9 ere suitehiy connected as by meansof conductors it, 12 and 13, that include main hiow-out windings 3.4;which are thus in pereiiei to the resin contuct members.

To open the circuit the main contact arm and the ercing contact orrn ereswung to the right, in Fig, 1 toy menus or the toggle mechsnisrnend 5,chore mentioned. This iinksge is so errenged that in opening the circuithreuker, the brush 3 is first titted from the contact mernhers therebydiverting the line current from the hrush 3 into the shunting circuitthrough the ercing contact arm 7, arcing contact shoe 8, stationerycontact memher 9, conductors H, 12 end 13, and hiowout winding it.Further movement of the linkage tuiiy opens the circuit by swinging thearm 7 further to the right thus tiringing shout disengagement oit thearcing con tact shoe 8 from the stctionery srcingcontact member 9 attheir nrcing tips.

k A pair of euxiiiery contact mernhers15 thst ere arranged to he openedsomewhat inter then the main contact members i, 2, 3., hut somewhatearlier then the resin contact tips 8 end 9, ere usushy provided toreiiere the main contact melnhers oi dent to the transfer oi currentfrom the resin brush to the inductive shunt circuit which includes theblowout coii it end the urcing contact members 8 and 9. Contact urrn isconnected near its hinge to contact nicrnher 2.

through the previously mentioned flerihie conductor 13 to complete atpath through the contacts 21. end 2 from contact memher 8 to contactroemher 9.

The are extinguishing structure 6, to which the invention is principallydirected coroprises so are chute which extends shove the space where theore is drown hetwcen tips of the arcing contact members. 8 and 9, Theare shoe comprises at pair of horn-hire inciined arcing pistes it and1'? to which the are drawn hetween the arcing tips of the arcing contactmembers 8 and 9 is trensterred hy the action of the resin blow-outmagnet. The hiow-out magnet comprises a terminated core 18 thatiscncited hy the previousiy mentioned hiow-out winding 14:, and s pairof pole shoes l positioned on op site sides of the urcing-horn plates itend 1 e upper ends of the inclined arcing horn pistes are ,nletciiiccliyconnected to vertical arcin pistes 21,22 as shown by Fig.1.

The poleshoes 19 end the vertical arcing pistes 21, 22 thus define astraight rectangutor chamber having at its lower end an upwardiy-taperedarc entrance chamber 23 orthe arcing incithe inclined arcing-horns 16,17 and then upwardly along the latter through the entrance chamber 23until it reaches the straight portion of the arcing chamber.

The straight portion of the arcing chamber between the arcing plates 21,22 is filled with a series of what may be termedsectionalized or laddergrids 24, each one comprising a series of parallel metal rods 25, theends of which are fastened in side plates 26 of high resistancematerial; the magnitude of the resistance of the side plates willdepend, in ways that will be obvious to those skilled in the art, on thevoltage and current rating of the circuit breaker; but for most ordinarypurposesit will be found suflicient to proportion the side plates 26 sothat the resistance intervening between successive bars 25 is aboutequal to that of a ten ampere arc of the same length in the atmosphereby which the bars are surrounded; that is to say the resistance may beabout three ohms for 0 an air breaker, Figs. 7 and 8 illustrate suchladder-grids in detail and Fig. 2 clearly shows their position in thedeionizing chamber. As shown by Figs. 1 and 3, the entire horizontallength of the chamber is occupied by a series of these verticalladder-grids. The thickness of the side plates 26 is such that themetallic bars 25 are separated from each other by equal spacings.Insulating strips 27 may be provided between the high resistance endmembers 26 of the adjacent grids to separate them electrically from eachother. To obtain a material for the plates 26 having suificiently highresistance, an insulating composition may be emplo ed into which a smallamount of lamp black as been introduced.

The chamber containing these ladder-grids is closed onits two verticalsides by plates 28 of insulating material but is left open at the top sothat it is possible for the heated gases incident to the operation ofthe arc to pass out of the chamber vertically.

The deionizing structure thus constituted may conveniently be heldtogether by through bolts 29 linking the end plates and compressing theladder-grids into a unitary rigid structure.

One desirable modification of thesimple structure just describedconsists in subdividing the deionizing chamber lengthwise by twometallic partitions 31, 32 as shown in the section in Fig. 1, Asillustrated in Fig. 4, resistances may be shunted between two pairs ofthe metallic plates. One'of these resistances may be of smaller valuethan the'other.

As a consequence of this arrangement, the arc drawn between the arcingtips 8, 9 will be forced by the blow-out magnet into the deionizingchamber and will'subdivide into three shorter sections. Just after thealternating current passes through zero, the voltage tending to reignitethe arc will rise more slowly on the section which is shunted by thelower resistance and the arc will be permanently extinguished in thissection at this time. The arcs in the remaining sections may reignite,but the current now is limited by the resistance shunting the section inwhich the are is extinguished.

In a similar manner, that one of the remaining arcs which is shunted bythe other resistance will be more readily extinguished than the arc inthe section which is not so shunted. It will be extinguished, therefore,in its turn, leaving the current flowing through the two shuntingresistors in series, and then through the arc in the remaining section.The effect of this considerable resistancein series with the arc is todecrease the current therein and to facilitate its extinction on thenext passage of the alternating current through zero. When it is soextinguished the entire circuit is, of course,

By this ex edient of interrupting the are by a series 0 separate steps,it is possible to interrupt heavier currents than would be possible ifthe entire interrupting operation had to take place at a single instant.

The voltage necessary to maintain the arc in the grids, is veryconsiderably greater than that necessary to maintain an arc of the samelength and current in the open air. On this account it is sometimesdiflicult to blow the are into the structure, since in splite of themagnetic field, a lower voltage may be able to maintain the are justoutside the grids than within them. It is also found that with greaterspacing between the bars, the arc voltage in the grids is less, and thearc passes more easily into the grid structure. The arrangement of Fig.8 has, therefore, been found to be of advantage in many instances,inasmuch as the spacing of the bars is there made greatest at the lowerend of the grid thus facilitating the entry of the are into the grids,and the spacing is made less and less with a corresponding increase ofefficiency in deionization at the upper end of the grid wherethe arcis'to be extinguished.

While this modification of the invention is of advantage in many cases,certain others 1 arise in which this more elaborate structure is notwarranted, and the simpler structure of Fig. 7 may then be employed withadvanta e.

The mode of operation of the circuit breaker will now be clear. Upon theopening of the main contacts, 1, 2, 3, the line current is transferredthrough the conductors 11, 12,

i3 and blowout-magnet to the arcing arm 7 and the arcing-horn the arcingarm moves further to c right, its tip passes the lower end of the arcinghorn 9 and thereby draws an arc therefrom. Upon its still furthermovement to the right, the end of this are is transferred Tom the arcingarm 7 to the other arcing horn l? as the arc is blown upward in thearcing chamber under the influence or? the biBW-fiufi magnet. Thedeflecting action of this magnet on the arc causes it to travel upwardalcng the arcing horns l6, 17 into the dcionizing structure abovedescribed. There it is c-ompeiied to opcrate in the spaces between therods oi the Rudder-grids, and the proximity of metallic members tend todcionise such portions of the arcs as are in proximity thereto.

As soon as it has been forced into contact with the vertical metalpartitions 31, 32, the arc is subdivided into three shorter sections ashas already been described. 'll'hc deflecting force of the blow-outmagnet forces the are continually upward through the deionizing chamber,thereby preventing it from remaining at any one place long enough todestructively overheat the bars of the ladder-grids. In the course ofthe alternating current cycle, the line current passes its maximum anddecreases to the value zero. When it reaches this value the interior ofthe deionizing chamher is still conductive due to the presence thereinof a large number of positive and negactive ions which constituted thecurrent carriers of the arc, and which momentarily remain free due tothe high temperature of the gases constituting an arc path. However, themetallic rods absorb the thermal energy and take up the electricalcharge from such ions as come in contact withthem, and thereby rapidlydeionize' the space in their immediate neighborhood. As the alternatingvoltage starts to rise on the reverse half cycle, it draws such freeions as may still remain uncombined in the arc path into contact withone or the other of the metal bars and immediately discharges them andefiects their rapid recombination. The metallic bars,thcrefore, rapidlydeionizc the arc path and may do this so rapidly that the alternatingvoltage is insuificient to produce an appreciable amount of ionizationby collision. Accordingly the flow of current through the are neverrises beyond a small leakage value and the circuit is eifectivelyinterrupted.

As has been stated, the expedient of subdividing the are by threeseparate chambers, and th; use of resistance shunts, makes it possible.that this electrical instabiiity may occur in the chamber shunted by thelowest resistance although it does not occur in the unshunted chamber.By this expedient of extinguishing the arc in stages, total currentswhich would be too great for a singie satanic unsliunted structure toeliectively deionize can be successfully coped with.

The deionizing structure which has been described, therefore, renders itpossible to cause deioniz-ation of arcs of large current value withoutdanger of transfer of. the arc to the separate metallic membersconstithb;

While in accordance with the patc'ntstatutcs the foregoing details ofthe practical embodiment of the invention have been given,-

it is to be understood that many of these are merely illustrative andthat variations from the precise formwill be desirable in designingcircuit interrupters for other voltages and currents than thosespecified above.

The principles which have been embodied in the circuit breakerinterrupter are applicable to many other purposes than those heredescribed as will be evident to persons skilled in the electrical arts.I is desired, therefore, that the language of the accompanying claimsshall be accorded the broadest construction of which it is reasonablysusceptible and that the invention shall belimited only by what isexplicitly stated in the claims and by the prior art. i What is claimedis:

1. In an arc'extin hing device, an arc chamber substantially filled witha multi licity of rods of conducting material, eac of said rods being saced from all of the other of the rods in t e an chamber and beingmountedb means providing a considerable resistance etween each rod andeach of the other rods adjacentthereto in any direction.

2. In an arc extinguishing device, an arc chamber having therein aplurality of rows of rods of conducting material, each of said.

rods being spaced from all of the other of the rods in t e are chamberand being mounted by means interposing an impedance between adjacentrods in any direction at'least equal to the impedance of an are at 10amperes in the atmosphere of said chamber and of the. same length as thedistance between adj acent rods. 7 I

3. In combination, means to establish an are, means forming an arcextinguishing chamber and having amultiplicity of sepafrom adjacent theend of said chamber adja cent said means to establish the are to adjacent the opposite end thereof, said conduct ing elements providingconducting paths. across the arc; extinguishing chamber only rateconducting elements positioned therein 1% from side to side, and theresistance between adjacent conducting elements in any direction beingsubstantially more than three ohms.

4. In combination, means to establish an are, means forming the sidewalls of an arc extinguishin device, a multiplicity of separateconductrn elements extending between said side we s over a considerablearea thereof, said conducting elements being insulated from each otherin all directions for the portion of their length between said sidewalls and having their ends supported by said side walls, and said meansforming the side walls providing considerable resistance between theends of said conducting elements.

5. In combination, means to establish an arc, an arc extinguishingdevice, means for causing movement of the arc in said are extinguishingdevice, and a multiplicity of conducting elements positioned in'said areextinguishing device at intervals s aced along the direction of movementof t e arc, said conducting elements extending only in a direction whichis both transverse to the length of the arc and transverse to thedirection of movement of the arc. v

6. In combination, means for causing an are, means for extinguishing thearc includin a stack of grids each positioned in a plane su stantiallytransverse to the arc, each of said grids including a pair of edgemembers and a plurality of conducting wires spaced from each other andhaving their ends secured to said edge members, and the material of saidedge members providing a resistance between adjacent wires at least asgreat as the resistance of a 10 ampere arc in air.

7. In combination, means to establish an arc and deionizing meanscomprisin bars of conducting material transverse to t e are path andresistance means interposed between the adjacent ends of the bars, thespacing of said bars var ing with their distance from said areestablishing means.

8. In combination, means to establish an arc and deionizing meanscomprisin bars of conducting material transverse to t e are path andresistance means interposed be-' tween the adjacent ends of the bars,the spacing of the bars nearest said arc-establishing means bemg greaterthan that of the bars farthest from said arc-establishing means. 9. Incombination, means to establish an arc and a deionizing chambercontaining bars of conducting material transverse to the arc path, meansto interpose between adjacent bars a resistance of substantially morethan three ohms, the spacing of the bars nearest said arc-establishingmeans being greater than that of the bars farthest from said areestablishing means.

10. In combination, means to establish an arc and deionizing meanscomprising conductors transverse to the arc path, the spacing of saidconductors varying with their distance from said arc-establishing means.

11. In combination, means to establish an arc, deionizing meanscomprising conductors transverse to the path of saidarc, means to movethe arc across said conductors, the spacing of said conductors varyingwith their distance from said are establishing means.

12. In combination, means to establish an arc, deionizing meanscomprising conductors transverse to the path of said arc, means to impelthe arc towards said conductors, the spacing of the conductors nearestsaid are establishin means being greater than that of the con uct-orsfarthest therefrom.

13. In combination, means to establish an arc, deionizing meanscomprising conductors transverse to the path of said are, resistancemeans interposed between the adjacent ends of the conductors, means tomove the arc across said conductors, the spacing of said conductorsvarying with their distance from said are establishing means.

14. In combination, means to establish an arc, deionizing meanscomprising conducting bars transverse to the path of said arc,resistances of substantially more than three ohms interposed between theadjacent ends of the bars, and means to deflect the arc towards saidbars, the spacing of said bars varying with their distance from said areestablishing means. 7 V

In testimony whereof, I have hereunto subgcribed my name this 18th dayAugust, 192 i SAMUEL'D. CRAGO, Administrator of the Estate of Alan 0.

Orago, Deceased.

